Prognosis and follow-up of patients with prosthetic valve endocarditis treated conservatively in relation to WBC-SPECT imaging.

BACKGROUND: Our objective was to evaluate in patients with prosthetic valve endocarditis (PVE) treated conservatively, the prognostic value of white blood cell (WBC) signal intensity on SPECT and to describe the evolution of the WBC signal under antibiotics. METHODS: Patients with PVE treated conservatively and positive WBC-SPECT imaging were identified retrospectively. Signal intensity was classified as intense if equal to or higher, or mild if lower, than the liver signal. Clinical, biological, imaging and follow-up information were collected from medical files. RESULTS: Among 47 patients, WBC signal was classified as intense in 10 patients and as mild, in 37. The incidence of the primary composite endpoint (death, late cardiac surgery, or relapse) was significantly higher in patients with intense vs. mild signal (90% vs. 11%). Twenty-five patients underwent a second WBC-SPECT imaging during follow-up. The prevalence of WBC signal decreased progressively from 89% between 3 and 6 weeks to 42% between 6 and 9 weeks and 8% more than 9 weeks after initiation of antibiotics. CONCLUSIONS: In patients with PVE treated conservatively, intense WBC signal was associated with poor outcome. WBC-SPECT imaging appears as an interesting tool for risk stratification and to monitor locally the efficacy of antibiotic treatment.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in polymyalgia rheumatica: an observational study.

OBJECTIVES: Polymyalgia rheumatica (PMR) is an inflammatory disease with a diagnosis that is sometimes difficult to establish. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) might be helpful. We analysed the usefulness of 18F-FDG PET/CT for the diagnosis of PMR. METHODS: This was an observational retrospective study of individuals with PMR who underwent 18F-FDG PET/CT and a control group. We assessed clinical and 18F-FDG PET/CT characteristics. Sixteen sites were studied. The number of sites with significant FDG uptake, the mean maximum standardised uptake value (SUVmax) and the highest SUVmax value were assessed for each patient. RESULTS: Data for 123 patients with PMR (37 with corticosteroids [CSTs] use) were analysed; 85 had new-onset PMR. As compared with the 75 controls, patients with new-onset PMR had higher mean ± SD number of sites with significant FDG uptake (11.3 ± 3.3 vs. 0.9 ± 1.1, p<0.001) and higher SUVmax scores (p<0.001). A cut-off of 5 hypermetabolic sites provided sensitivity of 96.5% and specificity 100%. For the total SUVmax score, a cut-off of 3 had the best sensitivity (92.6%) and specificity (86.1%). As compared with PMR patients using CSTs, those who were CST-naive had significantly higher CRP level (p<0.001), number of sites with significant FDG uptake (p<0.001) and SUVmax scores (p<0.01). In contrast, large-vessel vasculitis was more frequent in patients receiving CSTs than CST-naive patients (27% vs. 8%, p<0.01). CONCLUSIONS: The number of hypermetabolic sites or SUVmax quantification might be useful for PMR diagnosis, and CSTs might affect the results of 18F-FDG PET/CT.

Diagnostic performance of White Blood Cell SPECT imaging against intra-operative findings in patients with a suspicion of prosthetic valve endocarditis.

AIM: The objective of this study was to evaluate the diagnostic performance of white blood cells (WBC)-SPECT imaging in patients with suspicion of prosthetic valve endocarditis (PVE) against intra-operative findings. METHODS: 36 consecutive patients who underwent cardiac surgery 30 days after WBC-SPECT imaging were identified retrospectively. Clinical, imaging, and biological results were collected from reports. WBC-SPECT results were classified as positive or negative and, if positive, the intensity of signal graded as intense or mild. Lesions observed during cardiac surgery were collected from surgeons' reports. RESULTS: The 20 patients with positive WBC-SPECT study had confirmed PVE intra-operatively. Patients with intense signal on WBC-SPECT had high prevalence of abscesses (83%) compared to patients with only mild signal (12%). The three patients with negative WBC-SPECT but confirmed PVE had longer duration of antibiotic treatment before imaging and had no perivalvular abscess. Sensitivity, specificity, positive predictive and negative values, and accuracy of WBC-SPECT were measured at 87%, 100%, 100%, 81%, and 92%, respectively. Addition of WBC-SPECT results to the modified Duke score helped re-classify correctly 25% of patients from possible to definite PVE. CONCLUSION: In patients with suspicion of PVE, WBC-SPECT imaging provides excellent diagnostic performance against intra-operative findings.

Hypermetabolism of the spleen or bone marrow is an additional albeit indirect sign of infective endocarditis at FDG-PET.

PURPOSE: This study aimed at determining the diagnostic implications of indirect signs of infection at FDG-PET-i.e., hypermetabolisms of the spleen and/or bone marrow (HSBM)-when documented in patients with known or suspected infective endocarditis (IE). METHODS: HSBM were defined by higher mean standardized uptake values comparatively to that of the liver on FDG-PET images from patients with a high likelihood of IE and prospectively included in a multicenter study. RESULTS: Among the 129 included patients, IE was ultimately deemed as definite in 88 cases. HSBM was a predictor of definite IE (P = 0.014; odds ratio (OR) 3.2), independently of the criterion of an abnormal cardiac FDG uptake (P = 0.0007; OR 9.68), and a definite IE was documented in 97% (29/30) of patients showing both HSBM and abnormal cardiac uptake, 78% (7/9) of patients with only abnormal cardiac uptake, 67% (42/63) of patients with only HSBM, and 37% (10/27) of patients with neither one. CONCLUSION: In this cohort with a high likelihood of IE, HSBM is an additional albeit indirect sign of IE, independently of the criterion of an abnormal cardiac uptake, and could reinforce the suspicion of IE in the absence of any other infectious, inflammatory, or malignant disease.

FDG atrial uptake is associated with an increased prevalence of stroke in patients with atrial fibrillation.

PURPOSE: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with an increased risk of stroke. Indeed, silent AF is frequently identified in unexplained ischemic stroke. 18F-FDG-PET/CT is a powerful tool for assessing myocardial metabolic shift and inflammation, both potentially at stake in AF. This case-control study investigated whether AF could promote FDG uptake in atria after physiological myocardial glucose uptake suppression, and the potential relationship between FDG atrial uptake and prevalence of stroke. METHODS: We retrospectively enrolled 128 patients (64 consecutive patients with AF and 64 without AF as the control group, matched for age and sex) who underwent 18F-FDG-PET/CT after a high-fat low-carbohydrate diet. We analyzed visual and quantitative FDG uptake parameters of the right and left atria (RA/LA) and the right and left appendages (RAA/LAA), and selected clinical features including history of stroke. RESULTS: Diffuse right atrial uptake was present in a third of patients with AF and only two patients in the control group. FDG uptake intensity of both atria was significantly associated with the underlying heart rhythm. The occurrence of stroke was strongly associated with detectable atrial uptake in multivariate analysis, with an odds ratio superior to that of other known risk factors. CONCLUSIONS: This study shows a significant correlation between FDG atrial uptake and AF. While inconsistent, this pattern seems to be associated with an increased prevalence of cardioembolic stroke.

Cardiac denervation evidenced by MIBG occurs earlier than amyloid deposits detection by diphosphonate scintigraphy in TTR mutation carriers.

PURPOSE: Cardiac involvement in familial transthyretin (TTR) amyloidosis is of major prognostic value, and the development of early-diagnostic tools that could trigger the use of new disease-modifying treatments is crucial. The aim of our study was to compare the respective contributions of 99mTc-diphosphonate scintigraphy (DPD, detecting amyloid deposits) and 123I-MIBG (MIBG, assessing cardiac sympathetic denervation) in patients with genetically proven TTR mutation referred for the assessment of cardiac involvement. METHODS: We prospectively studied 75 consecutive patients (classified as symptomatic or asymptomatic carriers), using clinical evaluation, biomarkers (troponin and BNP), echocardiography, and nuclear imaging. Patients were classified as having normal heart-to-mediastinum (HMR) MIBG uptake ratio 4 h after injection (defined by HM4 ≥ 1.85) or abnormal HM4 < 1.85, and positive DPD uptake (grade ≥ 1 of Perugini classification) or negative DPD uptake. RESULTS: Among 75 patients, 49 (65%) presented with scintigraphic sympathetic cardiac denervation and 29 (39%) with myocardial diphosphonate uptake. When MIBG was normal, DPD was negative except for two patients. Age was an independent predictor of abnormal scintigraphic result of both MIBG and DPD (HR 1.08 and 1.15 respectively), whereas echocardiographic-derived indicators of increased left ventricular filling pressure (E/e' ratio) was an independent predictor of abnormal MIBG (HR 1.33) and global longitudinal strain of positive DPD (HR 1.45). In asymptomatic patients (n = 31), MIBG was abnormal in 48% (n = 15) among whom 50% had a normal DPD; all those with a normal MIBG (n = 16) had a normal DPD. CONCLUSIONS: In TTR mutation carriers, cardiac sympathetic denervation evidenced by decreased MIBG uptake is detected earlier than amyloid burden evidenced by DPD. These results raise the possibility of a diagnostic role for MIBG scintigraphy at an early stage of cardiac involvement in TTR-mutated carriers, in addition to its well-established prognostic value.

18F-FDG-PET/CT Imaging to Diagnose Septic Emboli and Mycotic Aneurysms in Patients with Endocarditis and Cardiac Device Infections.

PURPOSE OF REVIEW: This review analyzes recent studies evaluating the diagnostic value of 18F-FDG-PET/CT for the detection of peripheral emboli and secondary infectious foci in patients with infective endocarditis and cardiac device infections. RECENT FINDINGS: Detection of extracardiac septic localizations in patients with infective endocarditis and cardiac device infections is crucial, as it may impact the diagnosis, prognosis, and therapeutic management. Recent literature substantiated the clinical usefulness of 18F-FDG-PET/CT in this setting. 18F-FDG-PET/CT has proven its high diagnostic value for the detection of peripheral emboli in patients with infective endocarditis and cardiac device infections, substantially affecting patients' outcome and treatment. A multimodal approach, combining the high sensitivity of 18F-FDG-PET/CT with morphological imaging seems promising.

Cardiovascular Imaging in Women.

Multimodality cardiovascular imaging is a cornerstone diagnostic tool in the diagnosis, risk stratification, and management of cardiovascular diseases, whether those involving the coronary tree, myocardial, or pericardial diseases in general and particularly in women. This manuscript aims to shed some light and summarize the very features of cardiovascular disease in women, explore their unique characteristics and discuss the role of cardiovascular imaging in ischemic heart disease and cardiomyopathies. The role of four imaging modalities will be discussed including nuclear medicine, echocardiography, noninvasive coronary angiography, and cardiac magnetic resonance.

Absence of infective endocarditis relapse when end-of-treatment fluorodeoxyglucose positron emission tomography/computed tomography is negative.

AIMS: In non-operated infective endocarditis (IE), relapse may impair the outcome of the disease. The aim of the study was to evaluate the relationship between end-of-treatment (EOT) fluorodeoxyglucose positron emission tomography/computed tomography FDG-PET/CT results and relapse in non-operated IE either on native or prosthetic valve. METHODS AND RESULTS: We included 62 patients who underwent an EOT FDG-PET/CT for non-operated IE performed between 30 and 180 days of antibiotic therapy initiation. Qualitative valve assessment categorized initial and EOT FDG-PET/CT as negative or positive. Quantitative analyses were also conducted. Clinical data from medical charts were collected, including endocarditis team decision for IE diagnosis and relapse. Forty-one (66%) patients were male with a median age of 68 years (57; 80) and 42 (68%) had prosthetic valve IE. End-of-treatment FDG-PET/CT was negative in 29 and positive in 33 patients. The proportion of positive scans decreased significantly compared with initial FDG-PET/CT (53% vs. 77%, respectively, P < 0.0001). All relapses (n = 7, 11%) occurred in patients with a positive EOT FDG-PET/CT with a median delay after EOT FDG-PET/CT of 10 days (0; 45). The relapse rate was significantly lower in negative (0/29) than in positive (7/33) EOT FDG-PET/CT (P = 0.01). CONCLUSION: In this series of 62 patients with non-operated IE who underwent EOT FDG-PET/CT, those with a negative scan (almost half of the study population) did not develop IE relapse after a median follow-up of 10 months. These findings need to be confirmed by prospective and larger studies.

Diagnostic Impact of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and White Blood Cell SPECT/Computed Tomography in Patients With Suspected Cardiac Implantable Electronic Device Chronic Infection.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) chronic infection diagnosis is challenging because the clinical presentation is frequently misleading and echocardiography may be inconclusive. The aim of this study was to evaluate the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (CT) and radiolabeled white blood cells single photon emission CT/CT in a cohort of patients who underwent both scans for suspicion of CIED infection and inconclusive routine investigations. METHODS: Forty-eight consecutive patients with suspicion of CIED infection who underwent both 18F-fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT in a time span ≤30 days were retrospectively included. The final diagnosis of CIED infection by the endocarditis expert team was based on the modified Duke-Li classification at the end of follow-up. 18F-Fluorodeoxyglucose positron emission tomography/CT and white blood cell single photon emission CT/CT scans were independently analyzed blinded to the patients' medical record. RESULTS: In the overall study population, the diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were respectively 80%, 91%, 80%, and 91% for 18F-fluorodeoxyglucose positron emission tomography/CT and 60%, 100%, 100%, and 85% for white blood cell single photon emission CT/CT. Addition of a positive nuclear imaging scan as a major criterion markedly improved the Duke-Li classification at admission. Semiquantitative parameters did not allow to discriminate between definite and rejected CIED infection. Prolonged antibiotic therapy before imaging tended to decrease the sensitivity for both techniques. CONCLUSIONS: Nuclear imaging can improve the diagnostic performances of the Duke-Li score at admission in a selected population of patients with suspected CIED infection, particularly when the infection was initially graded as possible. Whenever possible, imaging should be performed before or early after antibiotic initiation.

Comparison between visual and numerical metrics for the evaluation of patients with Takayasu arteritis with 18F-FDG-PET.

INTRODUCTION: The choice of metrics for defining active Takayasu arteritis (TAK) using fluorine-18-fluorodeoxyglucose (F-FDG)-PET remains controversial. OBJECTIVE: The aim of this study was to compare in the same patients the diagnostic performance for the detection of active TAK of different metrics applied for the quantification of vascular F-FDG uptake with PET. PATIENTS AND METHODS: Overall, 62 PET acquisitions were performed 90 min after F-FDG injection in 15 patients with TAK and analyzed retrospectively. The intensity of vascular F-FDG uptake was graded visually in comparison with the liver signal and with the numerical metrics, including maximum standard uptake value (SUV), maximum target to background ratio (TBR, ratio of SUVmax in the vessel wall and SUVmean of blood), most-diseased segment (MDS)-TBR (average of TBR from all active lesions), and global TBR (average TBR along the aorta and carotid arteries). The gold standard was disease activity identified using the National Institute of Health score for TAK. RESULTS: Using visual analysis, the definition of F-FDG-PET as positive in presence of at least one vascular lesion with a signal more than liver provided the best diagnostic performance for detecting active TAK with a specificity of 98%, a sensitivity of 62% and an accuracy of 89%. Using numerical metrics, SUVmax [SUVmax >3.3; area under the curve (AUC)=0.84] and TBRmax (TBRmax >2.3; AUC=0.84) offered the best diagnostic performance for the detection of active TAK in comparison with MDS-TBR (MDS-TBR>1.7; AUC=0.70) and global TBR (global TBR >1.4; AUC=0.51). CONCLUSION: In this study, we found that the analysis of the vascular region with the highest F-FDG uptake using either visual or numerical metrics provided the best diagnostic performance for the detection of active TAK with PET.